Once the human technology develops, the study of its influence over the environment, the soil, the water, the flora and the fauna is becoming increasingly important. In communism, due to the lack of integrated management of water resources, the quality of the waters in Romania has constantly worsened. In the same time, the quality of the waters of the Jiu River has worsened. After 1990, especially after Romania's EU accession, our country was obligated to pass a rigorous environmental control which also includes legislation according to the international norms. Our work aims to analyze if the integrated management of water resources is applied to the Jiu River course and also, aims to analyze the evolution of the concentration of heavy metals in Jiu River course in the coming years using a mathematical forecasting model.

In this work, diesel soot has been characterized chemically using a diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) technique. Diesel soot samples were generated under combustion conditions reproducing the typical urban operating mode of a diesel engine. Initial experiments performed to ensure the repeatability of the Drifts analysis and the sample preparation method showed that the standard deviations were always lower than 20% for the DRIFTS analysis itself, and lower than 25% when sample preparation was included. This is of special interest as regards application of the DRIFTS technique for quantitative analysis. The functional groups on the soot surface were identified on the basis of the infrared bands observed in the spectra at room temperature, indicating that the diesel soot analyzed comprises a mixture of aromatic hydrocarbons, carboxylic compounds, hydroxyl species, ether groups, and methylene and methyl groups. Analyses were also carried out at different temperatures in the interval of 298-858 K in order to analyze the thermal stability of the functional groups, with carbonyl groups, lactones and ethers appearing to be the most thermally stable compounds.

Water balance studies in the Okavango Delta indicate that more than 90% of inflow into the Delta is lost through evaporation. This coupled with high climatic variability threatens the ecohydrology of the Delta. Trends indicate decreasing rainfall amounts and increasing temperature at the area of the Delta. The main aim of this study was therefore to investigate long term trends and variability in rain onset, cessation, number of rainy days and their impact on the dryness index at the Delta. The impact of the above variables is expressed through the standardized precipitation and evaporation index (SPEI) quantified by aggregating the climate water balance and fitting monthly series to a generalized logistic distribution using L-Moments. The SPEI, determined at windows of different time scales of one, three and twelve months, provided an extensive evaluation of dryness severity and its impact on this sensitive ecosystem. Rain onset and cessation dates were generated from cumulative pentad rainfall–evapotranspiration relationships. Analysis of climatic data showed mean rain onset occurring in November and ceding in March with average of 44 rainy days between 1970/71 and 2013/14. The results revealed a decrease in the number of rainy days at a rate of 0.16 days/yr and of the duration of the rainy season at 0.25 days/yr with high variability. Annual rainfall was found to decrease at the rate of 1.60 mm/yr with 6.8% probability of failure in rainfall onset. Analysis further revealed that both extreme dryness and wetness are rare phenomena with probabilities of less than 1% and near normal conditions for 67% of the time for all SPEI time scales. Although gradual increase in dryness in the Delta is attributed to high climatic variability, simulations undertaken using Artificial Neural Networks did not predict any major changes in the next five years. However, vulnerability to severe droughts is not completely ruled out because of the high variability in rainfall and of the location of the Delta in a semi-arid zone.

This paper proposes one new attempt to formulate a mathematical approach to climate parameters in the context of their complex implications for tourist activities through the tourism climate comfort index (TCCI). This paper also aims to formulate an original and optimal mathematical correlation between readily obtainable climate parameters (mean monthly air temperature, monthly amplitude of air temperatures, monthly insolation, average monthly relative air humidity and the number of rainy days), which results in values of the TCCI. Simultaneously, this index will provide the values correspondent to the values of air temperatures (°C), which represents a comparative baseline understandable equally for tourists, tourism planners and managers. The example of Serbia as a mainland country in the south-east of Europe was used to apply the proposed methodology. The spatial-temporal variability of TCCI is formulated on basis of data for the period 1961-2000 while for testing model was used selected period 2001-2010 on the sample of 26 meteorological stations distributed all around Serbia. For this purpose a standard statistical techniques were applied and ArcGIS software was used for analyze of the variability of the TCCI in relation to the altitude, which is of particular importance for the development of tourism in the mountains. Checking variability of the index was carried out in relation to statistical data about number of tourists on the three most visited tourist destinations which are of importance for the development of urban, mountain and spa tourism, the leading forms of tourism activities on the territory of Serbia. The obtained results correspond with the fact of the pronounced seasonality of tourism market and thus may represent a good basis for future tourism planning and management.

In the present study, monthly rainfall, maximum temperature and minimum time series models were developed for Jorhat (Assam) situated in northeast India using monthly rainfall, maximum temperature and minimum temperature data from the year 1965 to 2000. A trend free time series of rainfall and temperature was obtained by eliminating the trend component in the original time series, and then was used in identifying the periodic component. Fourier series analysis was used to identify periodic component. First five harmonics explained total variance of 79.4, 72.6 and 73.7% for monthly rainfall, maximum temperature and minimum temperature respectively. In the stochastic dependent component modelling, Autoregressive (AR) models of order 12 were found suitable on the basis of minimum value of AICC and BIC statistics. Portmanteau test formulated by McLeod and Li was carried out for checking the independence of stochastic dependent component which indicated that series consist of independent and identically distributed variables. Independent stochastic components were further modelled using normal distribution function. Nash-Sutcliffe coefficient also indicated high degree of models fitness to the observed data. Developed time series models were validated using eight years (2001-2008) data. Using the developed time series models, monthly rainfall, maximum temperature and minimum temperature were forecasted up to the year 2050. Assessment of changes in monthly rainfall, maximum temperature and minimum temperature in generated series (2009 to 2050) were predicted using linear regression which indicated no significant trend, i.e., the climate at Jorhat (Assam) in next four decades will remain more or less stable.

Biogas production through anaerobic co-digestion of a mixture of cattle manure and citrus waste using an experimental facility for testing the biochemical methane potential (BMP) was investigated. No buffer solution is added to the mixture in order to use the buffer capacity from cattle manure. Regular measurements of pH, alkalinity, chemical oxygen demand, methane and biogas net production were performed. Three substrate inoculum ratios (SIR) 1:1, 2:1 and 3:1 (g COD/g VSS) were evaluated. Maximum COD removals of 56.4 %, 51.3 % and 48.0 % for the SIRs 1:1, 2:1 and 3:1 were obtained. For all SIR, pH was on the range of 6.5 to 7.5, while the maximum VFA concentration was 4250 mg CH3COOH l-1. Alkalinity ranged between 2250 to 4500 mg CaCO3 l-1. Both maximum methane production rate (MMPR) and percentage of anaerobic biodegradability were established. BMP of 94.3 to 146.6 mLSTP-CH4/gVSS were calculated for the ratios 1:1 and 3:1, respectively. The highest feasibility for biogas production and methane was established for SIR 3:1.

Rapid development in industrial sectors and population expansion has adverse impact on the Cooum river basin, especially Chennai region. The present study focuses on the assessment of seasonal variation in surface water quality of Cooum river basin. The samples were collected seasonally and are categorized as pre-monsoon, monsoon and post-monsoon during March 2013 to March 2014. Eighteen physicochemical parameters were assessed for eleven different samples collected along the channel of Cooum river basin. Statistical tools such as correlation analysis scatter plots, box plot and multivariate tools such as cluster analysis and principal component analysis were applied to categorize the Cooum river water quality. From the data sets, the ionic concentration, organic loads exhibits positive correlation (R2>0.7) for all three seasons. Also, box plot and scatter plot results revealed that during post-monsoon season the ionic concentration along with organic and inorganic levels were slightly higher than monsoon and pre-monsoon. Similarly, multivariate statistical tools such as principle component analysis (PCA) indicate that the ionic concentrations and organic load contributed more than 50% of variance while cluster analysis (CA) reveals that nature of pollutant load among the sites.

In the present study, adsorption potential of potassium permanganate (Hypermangan) modified zeolite was investigated for the removal of nitrate from synthetic wastewater. Effects of the most significant parameters (pH, adsorbent dose, nitrate concentration and contact time) were initially evaluated based on the percentage of nitrate removed from the water solutions. Over 90 % removal of 150 mg L-1 nitrate was achieved at an optimum pH of 5, adsorbent dose of 2g L-1 after a 60 min contact time. The chemical and morphological characterizations of Hypermangan modified zeolite (HMZ) were carried out by using scanning electron microscopy (SEM), fourier transform infrared (FT-IR), x-ray diffraction (XRD) and x-ray fluorescence (XRF) analysis methods. Kinetic evaluation indicated that the nitrate adsorption onto HMZ followed the pseudo-first-order model. The equilibrium data assessment illustrated the removal of nitrate by HMZ follows a Langmuir model which attains the maximum adsorption capacity 6.7 mg g-1.The mean free energy of adsorption was 0.15 kJ mol-1, which indicates the adsorption of nitrate onto HMZ, occurs through a physical mechanism.

Athens in antiquity as well today, included all the settlements in the wider Attica region. That is why its official name was “the Athens” (plural). Since prehistoric times, the city of Athens and the wider region of Attica did not contain many natural water sources so aquatic reserves were never adequate to meet the needs of residents, as these changed through time. The construction of aqueducts was part of a more organized effort to address the water needs of the Attica basin area since prehistoric times. In the ancient city, tens of small and large aqueducts were built to meet the city's needs for water. The hydraulic structures of Athens were mostly underground, for safety reasons. The water was channeled through aqueducts to fountains. Many aqueducts were built during the pre-Roman period and they were often works of leaders or other eminent citizens of ancient Athens. A key step in developing the city’s water infrastructure took place during the Roman occupation of Athens when the Hadrianic aqueduct and the Hadrianic reservoir were built. The project was a huge achievement for the time and was one of the longest tunnels worldwide during the Roman era Construction began in 125 AD and was completed in 140 AD. The Hadrianic aqueduct was underground with natural flow requiring a small and continuous slope along the aqueduct. Wells, communicating through the aqueduct, were placed at regular intervals.

The main branch of the aqueduct - the central part of the Hadrianic, consists of the main tunnel, approximately 20 Km long, which starts from the foot of Mount Parnitha in the present day Olympic Village and ends up in the reservoir of Lycabettus, exploiting the water sources of Parnitha, Penteli and the Kifissos River. Gravity collected water from the water sources in the main tunnel and there was also the contribution of smaller aqueducts along the route. The secondary branches are composed of many transverse, which were designed to increase the water discharge capacity of the main aqueduct.

The Hadrianic was a project of continuous multi source collecting groundwater along its path. It was constructed below the surface at a depth of 2.5 to 40 m depending on the upper aquifer of the Athens basin, which fed local wells, in order to collect groundwater from that aquifer, too. The Hadrianic stopped being maintained during the Ottoman occupation and returned into service after the liberation of the city until it was gradually abandoned after the construction of modern water resource projects.